I've figured out what it is. They bought extra light bulbs for the scoreboard so it shows 100 minutes.
I think they nicked them from the floodlights due to them not being turned on when it darkened a bit int second half
Every outfield player on the books has to score before the seasons out and he's writing to the EFL complaining there aren't enough games.
The scoreboard not stopping at 45 and 90 mins is a plus. Nobody can doubt how much injury time has been played.